Electric wave amplifier



March 2, 1943- H. BERGER ET AL ELECTRIC WAVE AMPLIFIER Fild Oct. 25,1940 4 Sheets-$119M, 1

Figild AIAIA March 2, 1943.

H. BERGER ET AL ELECTRIC WAVE AMPLIFIER Filed Oct. 23, 1940 4Sheets-Sheet 2 v Inventor: flemzamz Berger f/zlr flerrz 'ger March 2,1943. H. BERGER ET AL ELECTRIC WAVE AMPLIFIER Filed Oct. 23, 1940 4Sheets-Sheet 3 'F'ig'. 3a.

Fig.3b

March 2, 1943. H.BERGER ET AL ELECTRIC WAVE AMPLIFIER 4 Sheets-Sheet 4Filed Oct. 25, 1940 Patented 2 1943 ELECTRIC WAVE Herman Berger andFelix Herrlger, Berlin, Germany; vested in the Alien Property CustodianApplication October 23, iaiasenal No. 362,464

In Germany November 30, 1939 4Claims.

In electron tubes used in connection with short waves the currentinduced in the electrodes by the action of the electron clouds'passingthe electrodes is as important as the current having its path determinedby conductive means. With electron tubes of the usual construction theinduced current and the conducted current cannot be separated from eachother and the co-operation of the two currents is dimcult to control.

' According to the present invention, in order to overcome such drawbackthese two currents are separated from one another by means of anelectrode system arranged to emit an electron beam which is modulated asto its velocity or density and is made to enter a chamber, the so--called Heil chamber.

This comprises a hollow space through which an electron beam isprojected and at the entrance portion of which the electrons arevelocity modulated and at another portion oflwhich energy is extractedfrom the moving electrons. In one known arrangement the high frequencyenergy is derived from the beam by two annular or latticed electrodesenclosed by a metallic envelope or bulb. The electron beam is controlledaccording to the present invention by an arrangement of grids of thecustomary type.

In the drawings, Figs. 1a. to 4a are schematic views which eachillustrate one embodiment of the invention while Figs. 1b to 4b arediagrammatic views representing respectively the same embodiments asFigs. la to 4a and in which the vacuum vessels are shown to be sectionedat right angles to Figs. 1a to 4a.

The basis of the electrode arrangement, Figs. la, 1b, is a standardpentode system that emits an electron beam which mainly is density-modulated, that is, modulated as regards the density of the flow ofelectrons. This beam enters a Heil chamber B of special construction.The electrode that serves to derive the high frequency energy fromchamber B comprises two annular or latticed component electrodes Aenclosed by a metallic envelope or bulb SE. An aperture D equal in widthto that of the electron stream enables currents to pass through theelectrodes A, A. Bulb SE is grounded and constitutes the vacuum vesselfor the electrode system, and it may be cooled by any suitable means, aswater, for instance. The deriving electrodes A, A receive only smallcurrents. The electron clouds produced by the control grid GI act toinduce in the electrodes A, A a current that becomes efiective in anoscillatory circuit L.

path in the electrode system itself such currents will be greatlyprevented from reacting on the flow of electrons.

The arrangement shown in Figs. 3a, 3b serves mainly to modulate theelectron current in its velocity. GI denotes a space charge grid bywhich the primary current is determined and kept constant. G2 indicatesa grid electrode to which a control circuit S is connected. Grid G3serves as a screening electrode. Thegrids GI, G2, G3 are to produce thevelocity-modulated electron beam. For this purpose the electronstravelling between the grids GI, G2 on the one hand and between gridsG2, G3 on the other hand must be so timed in their progression that inthe second space they always meet with a field of the same direction asin the first space, that is, the electrons are input accelerated and inpart checked. The grids are precisely the same as those employed in thestandard broadcast tubes. However, in comparison with the operativwavelength the distances between the grids may be much larger than inthe case of density-modulation. Preferably, in order to decrease thegrid currents the first three grids are given the same pitch of windingand are mounted that their turns are located one after another. ,Theelectrodes G4, G5, G6 are connected to positive and negative directpotentials .altemately and serve to concentrate the beam. The spacebetween grid G3 and the electrodes A also serves to conglobate thevelocity-modulated electron beam into a density-modulated beam, thisaction being spoken of as drift effect. Bulb SE and the electrodes Aconstitute the deriving system more fully involved in Figs. 3a, 312.

What is claimed is:

1. Apparatus for amplifying short wave energy comprising a hollow metalmember divided into two chambers by an apertured wall, an elongatedelectron emissive cathode in one of said chambers extending in a planeparallel to the plane of said wall and adjacent the aperture therein, amultiapertured grid mounted in said last-mentioned chamber between saidcathode and said wall, a tubular member in the other of said chamberssurrounding the path of electrons which are projected through saidaperture, a source of fixed positive potential connected to said tubularmember, a resonant circuit coupled to said tubular member and a resonantcircuit coupled to-said rid.

2. Apparatus for amplifying short wave energy comprising a hollow metalmember dividedinto a central chamber and two side chambers by two spacedparallel apertured walls, an elongated electron emissive cathode. insaid central chamber extending in a plane parallel to the planes of saidwalls and adjacent the apertures therein, a multiapertured arid mountedin said central chamber and surrounding said cathode, a tubular membermounted in each of said side chambers and surrounding the paths ofelectrons which are projected through said apertures, a source 01' fixedpositive potential connected to'said tubular members, a resonant circuitcoupled to said tubular mrembers and a resonant circuit coupled to said8 d.

3. Apparatus according to claim 1 further comprising a secondmulti-aperture grid mounted between said cathode and said grid, a thirdmultiapertured grid mounted between said last-mentioned grid and saidwall, and sources of fixed positive potential connected to said secondand third grids.

4. Apparatus according to claim '1 further comprising second andthirdgrids mounted between said arid and said wall, a source of positivepotential connected to said second arid and a source of negativepotential connected to said third grid.

nmmsrm BE GER. max HERRIGER'.

